World's Largest Solar Power Towersto Rise in California

by Tina Casey
Clean Technica, March 15, 2013

Two leading solar innovators have teamed up to build the world's largest solar power towers in California, and we can all thank Interior Secretary Kenneth Salazar for that. Abengoa and BrightSource Energy are the two companies involved in the project, a 500 MW (megawatt) utility scale behemoth called the Palen Solar Electric Generating System. Consisting of two 250-MW units, it will be located in a federally designated Solar Energy Zone in Riverside County, on public land administered by the Interior Department's Bureau of Land Management. It is expected to create 2,000 construction jobs (Keystone who?) when work starts at the end of this year, and it will generate enough clean energy to power 200,000 homes. Wait for it. . .Hey, we built this!

What Is A Solar Energy Zone?

We also got word today that Secretary Salazar has approved another 900 MW in new solar projects in the same Solar Energy Zone, so this is a good time to go over the whole concept of a Solar Energy Zone.

President Obama's Solar Energy Zone initiative was finalized just last October. The intent is to streamline the process for approving utility-scale solar projects on public lands. In the context of a long history of leasing public land for fossil fuel and mining operations, there's nothing new to see here.

The Riverside zone is one of 17 initial Solar Energy Zones located in Arizona, California, Colorado, Nevada, New Mexico and Utah.

The selection of the zones is based on solar potential, environmental impact and the availability of existing or planned transmission lines among other factors.

All together, the first 17 zones encompass a total of 285,000 acres of public land. To give you an idea of how pared-down that figure is from the amount of public land out there, another 19 million acres are potentially available for solar projects but were not included in the streamlined umbrella, and almost 79 million acres have been identified as "inappropriate for solar development" altogether.

World's Largest Solar Power Tower

The Palen Solar Electric Generating System is one fruit of the Concentrating Solar Power Alliance, which Abengoa and BrightSource launched last year along with Torresol Energy. The aim was to put concentrating solar power front and center in the U.S. energy market, and it seems to have worked.

Concentrating solar power systems basically consist of a field of specialized mirrors called heliostats which aim reflected sunlight onto a relatively small central collector. The concentrated solar energy creates steam that powers a turbine.

The highlight of the Palen system is a pair of 750-foot tall towers. The heliostats are pole-mounted directly into the ground, which eliminates the need to level the ground to install concrete bases.

As a sustainability bonus, the Palen project was initially approved as a facility covering 4,366 acres. The tech partnership between Abengoa and BrightSource resulted in an improved design that shrank the footprint down to 3,800 acres. The new design will also use half the water needed under the original plan (for those of you new to the topic, conventional solar arrays use water as a coolant).

Oh Snap, Google!

Err. . .by the way, if that thing about "world's largest solar power tower" rings a bell, you're probably thinking about a Google solar energy investment of $168 million back in 2011 for the Ivanpah Solar Generating System in the Mohave Desert.

Ivanpah is another BrightSource Energy project. It includes 173,000 heliostats, which sounds pretty impressive. However, the Ivanpah solar tower is "only" 450 feet tall, which was apparently a record back in 2011. Sorry, Google.
Interior Department Steps Up

Under the Obama Administration, the Interior Department has been transitioning federal land use goals from straight-up fossil fuel and mining development to include alternative energy on the same footing.

Aside from the Solar Energy Zone initiative, last August the Interior Department signed a memorandum of understanding with the Department of Defense, aimed at exploring vast stretches of military training grounds and other facilities for potential clean energy sites.
This all comes as noted outdoors enthusiast, CEO and former oil industry expert Sally Jewell is set to take the helm as President Obama's new Interior Secretary, so stay tuned